1. Field of the Invention
This invention relates to a process wherein a film containing at least one dye is contacted with a textile material in the presence of sufficient heat to cause the dye (or dyes) to sublime or vaporize and transfer some of it from the film to the textile material, and thereby provide textile material level dyed in a solid shade.
2. Description of the Prior Art
In recent years, it has become a common commercial practice to print textile material by subliming or vaporizing and transferring dyes from paper carriers printed or coated with disperse dyestuffs in the form of an ink or paste; i.e. dyestuff plus binder. The textile material is contacted with the printed paper carrier in the presence of heat. In some processes, heating is accompanied by pressure. In others, vacuum is applied during or after the heating step.
While superficially, it may seem possible to achieve level dyeings of textile materials by the abovedescribed techniques, due to economic and/or technological limitations, none has been reported in commerce. Possible reasons for the state of the commercial art reside in the nature of the dye carrier and the means available for coating it.
In order to achieve level dyeing of the textile material, the coating on the carrier must be very uniform. The gravure technique, wherein coated paper (e.g. by clay) is used, might seem to be capable of achieving uniform coating of the carrier with a dye (in the form of an ink). However, one cannot meter ink exactly across the entire length and width of the carrier paper so as to achieve level solid shade dyeing therefrom by heat transfer. Moreover, it is expensive, both in terms of capital investment and in operating costs. The lithographic printing technique does not provide a continuous surface from which ink or print paste can be transferred. Ink can be metered less exactly with the flexographic process than the gravure technique. The rotary screen printing technique requires the use of a water-based ink, but clay-coated paper may not be used, because the water would cause the paper to pucker. If other paper is used with water-based inks, the dye thereof penetrates into the microstructure of the paper, and on heating would diffuse further into the paper, making it impractical, if not impossible, to effect level dyeing from the paper to a textile material.
Markert et al., in U.S. Pat. No. 3,707,346, disclose heat transfer printing of textiles wherein one or more anthraquinone disperse dyestuff is applied to one or both sides of a carrier for which the disperse dyestuff do not possess affinity. Preferably, the carrier is paper, but a metal substrate is disclosed as well.
Bossard et al., in U.S. Pat. No. 3,915,628, also disclose the use of a carrier having no affinity for the compound (including dyestuffs) which is to be transfer-printed on textile material by vaporization in the presence of heat. Their carrier is a continuous, endless structure to which the varporizable material is applied by spraying, coating or printing. The endless inert carrier may be metal, such as aluminum or steel, plastic, water- and optionally solvent-resistant paper, or textile fabrics, which are optionally coated with a film of vinyl resin, ethyl cellulose, polyurethane resin or a polytetrafluoroethylene resin.
Mayer, in U.S. Pat. No. 4,056,352, discloses the continuous dry transfer of organic compounds (including disperse dyestuffs) to webs of air-permeable organic materials (including textile webs) by passing the webs and the organic compound carriers over at least one heating means and subsequently over at least one suction means. As a rule, the carrier possesses no affinity for the preparation that contains the compound to be transferred (e.g. the dyestuff preparation). The preparations are applied to the inert carrier continuously by spraying, coating or preferably by printing over part or all of the surface of the carrier. If the carrier is air-permeable, and depending on the sublimation behavior of the compounds to be transferred, the untreated or treated side of the carrier may be brought into contact with the surface of the web to be treated. If, as is preferred, the carrier is impermeable to air, only the treated side of the carrier is brought into contact with the surface of the web material to be treated.
Sublistatic Holding S.A., in U.K. Patent Specification No. 1,392,390, disclose dry heating a textile material in contact with a flexible support which is coated or impregnated with a layer of a dyestuff or an optical brightening agent so as to cause the dyestuff or brightening agent to sublime or vaporize, and thereby transfer the same to the textile web. Paper or aluminum, preferably a paper sheet or web coated with a varnish to make it impermeable to air, is disclosed for use as the flexible support.